Trial Access For Media Files From Media List

ABSTRACT

Embodiments of the present disclosure provide systems and methods for sharing media files. Briefly described, in architecture, one embodiment of the system, among others, can be implemented as follows. The system includes a file sharing application configured to initiate a communication session with a file server, where the file server manages download requests for media files listed on a dynamic list. Use of the media files is subject to a trial period that corresponds to a period that the media files remain on the dynamic list. The system further includes trial period checking logic configured to retrieve a new dynamic list and check whether a trial period for a media file has expired by determining whether the media file is listed on the new dynamic list and offer presentation logic configured to offer a user a license for continued use of a media file that has an expired trial period. Other systems and methods are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/229,897 entitled “Trial Access for Media Files from a Media List,” byDale Malik, filed on Sep. 19, 2005, the disclosure of which is herebyexpressly incorporated by reference in its entirety.

This application is related to co-pending U.S. utility patentapplication entitled “Trial Access Terms for Media Files” filed on Sep.19, 2005 and accorded U.S. application Ser. No. 11/229,937, by DaleMalik, which is entirely incorporated herein by reference and co-pendingU.S. utility patent application entitled “Trial Use of a Collection ofMedia Files” filed on Sep. 19, 2005 and accorded U.S. application Ser.No. 11/229,910, by Dale Malik, which is entirely incorporated herein byreference.

FIELD OF THE DISCLOSURE

The present disclosure is generally related to digital media files and,more particularly, is related to access management for digital mediafiles.

BACKGROUND

An owner of a media file is often concerned with managing use of adigital copy of the media file and controlling who is authorized to haveand use a copy of the media file. This problem is particularly pervasivein the music industry. Unless some type of protection scheme is used, itis often easy for a quality copy of digital music to be reproduced andfor unauthorized use of the work to occur. Thus, many music sharingservices, which enable users to download copies of musical works orother media recordings, require a user to purchase a license to use acopy of the digital music from the owner of the musical work before theservice transfers a copy of the digital music file to a user. Further,some music sharing services require a user to subscribe to a monthlyplan for receiving and using digital music. If the user cancels thesubscription, however, the user is unable to play previously downloadedmusic. Such services, however, do not authorize a user to test or trydigital music for a limited time, on a case by case basis, without a feebeing initially associated with the music. Thus, a heretoforeunaddressed need exists in the industry to address the aforementioneddeficiencies and inadequacies.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be appreciated that for simplicity and clarity of illustration,elements illustrated in the Figures have not necessarily been drawn toscale. For example, the dimensions of some of the elements areexaggerated relative to other elements. Embodiments incorporatingteachings of the present disclosure are shown and described with respectto the drawings presented herein, in which:

FIG. 1 is a block diagram illustrating a system for purchasing digitalcopies of a media work, or other content recorded in a digital mediafile according to the present disclosure;

FIG. 2 is a flowchart describing one embodiment, among others, of anapproach for purchasing a license for use of a media file after a trialperiod has elapsed in accordance with the system of FIG. 1;

FIG. 3 is a diagram demonstrating one scheme, among others, ofassociating usage data with media files and other related information inaccordance with the system of FIG. 1;

FIG. 4 is a diagram illustrating one scheme, among others, forassociating encryption/decryption keys and other related information tomedia devices in accordance with the system of FIG. 1;

FIGS. 5-9B are diagrams illustrating various schemes, among others, forformatting media file contents and associated encryption/decryption keyand trial access terms in accordance with the system of FIG. 1;

FIG. 10 is a flowchart describing one embodiment, among others, of amethod for managing access to digital media files in accordance with thesystem of FIG. 1;

FIG. 11 is diagram of an embodiment of a screen interface for notify auser of an expired trial period in accordance with the system of FIG. 1;

FIG. 12 is a flowchart describing one embodiment, among others, of anapproach for generating an offer to purchase a media license inaccordance with the system of FIG. 1;

FIG. 13 is a flowchart describing one embodiment, among others, of alicense offering process in accordance with the system of FIG. 1;

FIG. 14 is a block diagram of a general-purpose computer that canimplement various components of present disclosure in accordance withthe system of FIG. 1;

DETAILED DESCRIPTION OF THE DRAWINGS

The numerous innovative teachings of the present application will bedescribed with particular reference to the presently preferred exemplaryembodiments. However, it should be understood that this class ofembodiments provides only a few examples of the many advantageous usesof the innovative teachings herein. In general, statements made in thespecification of the present application do not necessarily delimit anyof the various claimed inventions. Moreover, some statements may applyto some inventive features but not to others.

Embodiments of the present disclosure provide systems and methods forsharing media files. Briefly described, in architecture, one embodimentof the system, among others, can be implemented as follows. The systemincludes a file sharing application configured to initiate acommunication session with a file server, where the file server managesdownload requests for media files listed on a dynamic list. Use of themedia files is subject to a trial period that corresponds to a periodthat the media files remain on the dynamic list. The system furtherincludes trial period checking logic configured to retrieve a newdynamic list and check whether a trial period for a media file hasexpired by determining whether the media file is listed on the newdynamic list and offer presentation logic configured to offer a user alicense for continued use of a media file that has an expired trialperiod.

Embodiments of the present disclosure can also be viewed as providingmethods for sharing media files. In this regard, one embodiment of sucha method, among others, can be broadly summarized by the followingsteps: retrieving a dynamic list of media files; downloading a mediafile that is contained on the dynamic list; detecting expiration of atrial period for the downloaded media file, the trial periodcorresponding to a period of time that the downloaded media file isincluded on the dynamic list; and prompting a user to obtain a licensefor continued use of an expired media file.

Other systems, methods, features, and advantages of the presentdisclosure will be or become apparent to one with skill in the art uponexamination of the following drawings and detailed description. It isintended that all such additional systems, methods, features, andadvantages be included within this description, be within the scope ofthe present disclosure, and be protected by the accompanying claims.

FIG. 1 is a block diagram 100 that illustrates a system for purchasingdigital copies of a media work, or other content recorded in a digitalmedia file, to users according to various embodiments described herein.Examples of digital media files encompass a variety of file formats ormedia, and the present disclosure is not necessarily limited to anyparticular type of digital format. Examples of digital media filesencompass a variety of file formats or media, and the present disclosureis not necessarily limited to any particular type of digital format. Forexample, media files may include but are not limited to sound files,video files, and audio-video files.

According to one embodiment, as demonstrated in FIG. 1, a user operatesa media player application 110, in which the media player application110 plays digital media files. The media files are transferred from aremote file server that has access to a database storing an assortmentof media files. The remote file server may be referred to as a mediaserver 120.

The media player application 110 is a software application stored inmemory 140 of a general-purpose computer 130, and the general-purposecomputer 130 communicates with the media server 120 via a communicationnetwork 150, such as, but not limited to, the Internet. A communicationnetwork 150 in accordance with the present disclosure may encompass avariety of types of networks that enable a media sharing application 160to communicate with the media server 120. As such, the general-purposecomputer 130 or other communication device may utilize wirelesscommunication or wireline communication techniques.

In addition, a media sharing application 160 resides in memory of thegeneral-purpose computer device 130. The media sharing application 160communicates with the media server 120 and facilitates retrieval ofcopies of digital media files from the media server 120. Further, themedia sharing application 160 is configured to organize locally storeddigital media files (e.g., via arrangement of local media libraries) onthe general-purpose computer 130 and may also set information associatedwith a log-in account for the media server 120 and/or informationassociated with downloaded media files. In some embodiments, a singleapplication performs the functionality of the media sharing application160 and media player application 110.

Note, the media sharing application 160 may be a web page or anInternet-based application that is launched by an Internet browserapplication 170. In some embodiments, the media sharing application 160displays to a user different options for browsing available media filesand requesting a copy of the media file to be transferred from the mediaserver 120 to the general-purpose computer 130. One embodiment forrequesting a media file from media server 120, in accordance with thepresent disclosure, involves downloading a copy of a digital media filethat may be used during a trial period. After which, the media file maynot be authorized to be used.

In some embodiments, a personal or portable computing device 180 mayalso be associated with a general-purpose computer 130 or communicationdevice that receives media files from the media server 120. The portablecomputing device 180 is equipped to store media files and to playcontents of the media files. For example, a user may download a mediafile from the media server 120 to a general-purpose computer 130. Then,the general-purpose computer 130 transfers the downloaded media file tothe portable computing device 180 via a data link between thegeneral-purpose computer 130 and the portable computing device 180(e.g., a universal serial bus (USB) data connection). Along with thetransferred media file, additional information is transferred that isnecessary to play the transferred media file, such as anencryption/decryption key for removing an encryption layer protectingthe media file and trial access terms that express the trial period forthe media file. In particular, the encryption/decryption key is used toencrypt contents of a file before it is transferred by the media server120 and to decrypt the contents of the media file before it is played bya media player application 110 or accessed by some other computerapplication. Generally, the trial access terms include parametersdefining the trial period for a particular media file. The trial accessterms may be organized utilizing different fields within a datastructure. These parameters, in some embodiments, may express the trialperiod in positive terms or negative terms. The trial access terms maybe embodied in a variety of forms. Some of which is discussedhereinafter.

The portable computing device 180 also features a media playerapplication for playing media files stored on the portable computingdevice 180. The media player application for the portable computingdevice 180 may be referred as a portable media player application (notshown).

One embodiment of an approach for purchasing a license for use of amedia file is now described with reference to a flowchart diagram 200 ofFIG. 2. In step 210, a digital rights management (DRM) scheme isimplemented that authorizes use of a digital copy of a media work for alimited period that may be stated in terms of time or usage or acombination of both time and usage. After the trial period ends, adesignated event triggers an offer to be made to a user to purchase alicense for continued use of the digital copy of the media work. If theuser buys a license, then the user is authorized to use the media workin accordance with the terms of the purchased license. If the userdeclines to buy a license, the user is prohibited from using the copy ofthe media work, since the trial period has expired. The designated eventthat triggers the offer process may be a different event in differentembodiments.

Referring back to FIG. 2, a trial period is checked and detected (220)to have expired for a particular copy of a media work (e.g., “song”) bya media sharing application. For instance, in some embodiments, a mediasharing application 160 checks the trial periods of media located on ageneral-purpose computer 130 upon activation of the media sharingapplication. In some other embodiments, the media sharing application160 may also check the trial periods of media located on ageneral-purpose computer 130, whenever the media sharing applicationlogs into a session with a media server 120. Further, in someembodiments, the media sharing application 160 checks the trial periodsof media files stored on the portable computing device 180 when themedia sharing application 160 detects that the portable computing device180 has been connected to the general-purpose computer 130 with themedia sharing application 160.

After the media sharing application detects an expired trial period, themedia sharing application 160 offers (230) a user an opportunity topurchase a license for continued use of the media. The media sharingapplication 160 may have prestored information for making an offer thatwas previously received by the media server 120. Further, thisinformation may be updated in a periodic basis with the media server120. Alternatively, in some embodiments, the media sharing application160 may receive information from the media server 120 for making anoffer to the user after detection that use of the media has expired inaccordance with terms defining authorized use of the media during thetrial period. These terms may be referred to as trial access terms.

In addition to presenting an offer or a variety of offers for purchasinga license for use of a media contained in a media file, the mediasharing application 160 also provides interface options for acceptingand providing additional information for purchasing the license oralternatively, for declining the offer(s). If a license is purchased forcontinued use, the DRM scheme protecting the media work is modified toauthorize the user to use the media in accordance with the terms of hisor her new license. For example, if the DRM scheme indicates a limiteduse associated with a media file by having a header portion of the mediafile containing trial access terms that define what uses of the mediafile are authorized or not authorized, this header portion may bemodified by a computer application on the general-purpose computer 130or on the media server 140 to contain new trial access terms thatcorrespond to a newly purchased license agreement. In embodiments wherea separate file or data structure is used to specify trial access termsof a particular media work, this separate data structure may be modifiedby a computer application on the general-purpose computer 130 to containnew trial access terms that correspond to a newly purchased license.

Referring back to FIG. 2, if the offer is declined (240) by a user, themedia and/or associated files (that help implement the DRM protectionscheme) are modified (250) and/or deleted to prohibit the user fromplaying the media. For example, in some embodiments anencryption/decryption key is provided to a computer application, so thatthe computer application may access a media file that is protected by anencryption layer. To decrypt the encryption layer, theencryption/decryption key is utilized. However, if a computerapplication is instructed to delete the encryption/decryption keybecause use of a media file is no longer authorized in accordance with atrial access terms, then contents of the media file is unable to beaccessed by the computer application. Alternatively, the media fileitself may be deleted, in some embodiments, by a computer applicationafter a trial period for the media file has expired. If the offer isaccepted, then the media and/or associated files are modified to enablethe user to have continued access to the contents of the media.

The particular event that triggers a license offering process may bedifferent for different implementations of the media sharing services.For example, in the case where a user utilizes a general-purposecomputer 130 to play media files downloaded from a media server 120, theactivation of the media sharing application 160 may launch a process forchecking locally stored media files for expired trial periods.Alternatively or in addition, the logging into a media server 120 by amedia sharing application 160 may also trigger a process, in thegeneral-purpose computer 130, for checking locally stored media filesfor expired trial periods.

Next, a variety of approaches are discussed with regard to checking fora trial period associated with a media file. In particular, when themedia player application 110 receives a request to play a particularmedia file stored on the general-purpose computer 130, the media playerapplication 110, in some embodiments, checks for trial access termsassociated with a particular media file. In some embodiments, the trialaccess terms may be included in a header to the media file itself. Forexample, the media server 120 may configure trial access terms within aheader of the media file before transferring the media file to ageneral-purpose computer 130 or other computing device.

Therefore, after a media file is received from the media server 120, themedia file is decrypted by the media player application 110 using anencryption/decryption key associated with the media file. After the fileis decrypted and the contents of the file are accessible, then the trialaccess terms are obtained from a header of the media file. The trialaccess terms are then checked by the media player application 110 and/ormedia sharing application 160 to determine whether trial access termsauthorize continued use of media file. To do so, usage data or timinginformation is evaluated by the media player application 110. Forexample, if the trial access terms authorize a particular media file tobe played a maximum of 5 times while on the dynamic playlist, the amountof times the particular media file has already been played is maintainedas usage data by a media player application 110 and the usage data isevaluated when the media player application receives a new request toplay the media file. Correspondingly, if trial access terms for aparticular media file authorizes the media file to be played for aperiod of one month while on the dynamic playlist, then the time atwhich the media file was first accessed may also be stored as usage dataand compared with current timing information when a new request forplayback of the media file is received by a media player application110.

Further, if trial access terms indicate that a particular media file maybe played 5 times in one month's time, then the media player application110 maintains a record of the number of times that a media file has beenpreviously played and also records or maintains the date that the mediafile was first played, so that the media player application 110 maycalculate the length of time that has transpired since the first use ofthe media file. The usage data, in some embodiments, is recorded inupdateable field(s) within the data structure containing the trialaccess terms, which may be part of the media file. Therefore, in someembodiments, the updateable fields and other trial access terminformation is transferable with the media content information in asingle file. An advantage of keeping the trial access terms and usagedata together with the media contents in a single file is that any mediaplayer or computer application, in general, that attempts to access thefile has access to all of these components to determine whether a trialperiod has expired for a media file.

Alternatively, in some embodiments, the usage data is stored separatelyfrom the media file and/or trial access terms. For example, the usagedata may be recorded as distinct files for each media file, in someembodiments. Alternatively, in other embodiments, usage data for avariety of media files may be stored in one file (by a media playerapplication 110 or other application), such as a table having differententries for different media files.

For example, FIG. 3 demonstrates one way, among others, of associatingusage data with media files and other related information. For instance,in FIG. 3, a particular media player (“PLAYER I”) 310 is associated witha particular encryption (or decryption) key (“KEY 1”) 320. Therefore,media files transferred to a general-purpose computer 130 or othercomputing device housing the media player application 310 are encryptedand decrypted using the encryption/decryption key associated with themedia player application 310, in some embodiments. In particular, themedia server 120 assigns an encryption/decryption key to thegeneral-purpose computer, in some embodiments and passes a copy of thekey to the general-purpose computer. Therefore, when the media server120 encrypts a media file using the encryption/decryption key, the mediaplayer 310 on the general-purpose computer utilizes the key to decryptthe media file.

As represented in FIG. 3, a particular media file (“MEDIA FILE 1”) 330is also associated with the encryption/decryption key (“KEY 1”) 320,since the media file is encrypted using the particularencryption/decryption key 320. Thus, a media server 120, for example,may assign a particular encryption/decryption key to a particularcomputer or communication device that requests a media file from themedia server 120, and before transferring the media file (or as part ofthe transferal process), the media server 120 encrypts the media fileusing the encryption/decryption key. Accordingly, theencryption/decryption key is passed to the computer or communicationdevice housing the media player application, so that the media playerapplication located on the computer or communication device can use theencryption/decryption key to decrypt the media file to access thecontents of the media file.

Correspondingly, any potential information that is transferred from themedia server 120 to a computer or communication device may be encryptedusing the encryption/decryption key associated with the computer orcommunication device receiving the information. As such, trial accessterms 340 that are associated with a particular media file may also beencrypted using the encryption/decryption key, as represented in FIG. 3.

To gauge whether trial access terms 340 of a particular media fileauthorize continued use of a particular media file, usage data 350 ismaintained for each media file, as represented in FIG. 3. By comparingthe usage data that reflects the types of use a media file hasexperienced with the trial access terms that describe the types of usesauthorized for the media file, a media player application 310 or otherdevice can determine whether continued use of the media file isavailable or whether the trial period for using the media file, inaccordance with the trial access terms 140, has expired.

In one embodiment, among others, as shown in FIG. 4, distinctencryption/decryption keys are assigned for the respective devices. Onedistinct encryption/decryption key 420 is assigned to thegeneral-purpose computer having a media player application or device 410and one distinct encryption/decryption key 460 is assigned to a portablecomputing device 480 with a portable media player application. Thisassures that the encrypted media files stored on a particular device areconfigured to be accessed by a single device having theencryption/decryption key associated with the appropriate media file.Therefore, a user may register a general-purpose computer 130 with logicof the media server 120 in addition to a portable computing device 180,and logic of the media server 120 may assign one uniqueencryption/decryption key to the general-purpose computer 130 andanother unique encryption/decryption key to the portable computingdevice 180. The general-purpose computer 130 may pass theencryption/decryption key for the portable computing device 180 to theportable media player 180 from the media server 130.

Therefore, the media player application (PLAYER 1) 410 is associatedwith an encryption/decryption key (KEY 1) 420 which is associated withtrial access terms (TAT 1) 440 and a media file (MEDIA FILE 1) 430 andusage data (USAGE DATA 1) 450 that tracks how the media file has beenused. Correspondingly, a portable computing device (PLAYER 2) 480 isassociated with the general-purpose computer 130. Further, the portablecomputing device (PLAYER 2) 480 is associated with anotherencryption/decryption key (KEY 2) 460 which is associated with a set oftrial access terms (TAT 2) 470 and a media file (MEDIA FILE 2) 485 andusage data (USAGE DATA 2) 490 that tracks how the media file has beenused, in one embodiment.

As another example, FIG. 5 demonstrates one scheme, among others, forformatting a media file and associated files. For example, in FIG. 5, anencrypted media file 510 is shown. The encryption/decryption key 520associated with the encrypted media file 510 is also shown and stored inthe computer or communication device, where the media file 510 islocated. Trial access terms (TAT) 530 are also stored in a separate filethat may not be encrypted. Each of these files is accessible by acomputer application that manages media files for a user or attempts toaccess media files for a user. Accordingly, a computer application thatreceives a request from a user to access contents of a media file mayevaluate associated trial access terms to determine if the user isauthorized to access the media file.

Correspondingly, FIG. 6 demonstrates another scheme for formatting mediafile contents and associated encryption/decryption key and trial accessterms. In this example, the trial access terms 610 are included in afile structure with the media file contents 620, and the whole file isthen encrypted with an encryption layer 640 using a uniqueencryption/decryption key 630. To access the contents of the trialaccess terms 610 and media file contents 620, the encryption/decryptionkey 610 is used by a computer application to decrypt the encryptionlayer 640 that is protecting the media file 600.

As another example, FIG. 7 demonstrates another scheme for formatting amedia file and associated data structures. In this embodiment, trialaccess terms 710 may be added as a separate part of a file structurecontaining an encrypted media file 720, as shown in FIG. 7. In this way,the portion of the file structure containing the trial access terms 710may be accessible without an encryption/decryption key. However, toaccess the contents of the media file 720, an encryption/decryption key730 is used.

Alternatively, FIG. 8 demonstrates another scheme where the trial accessterms 810 and the media file contents 820 are organized in separate datastructures or files. Each structure is encrypted and protected by anencryption layer 830, 840 using an encryption/decryption key 850.Further, in FIG. 9A, a scheme is shown where the trial access terms 910are included in a file or data structure 920 that also contains theencryption/decryption key 930 for an associated media file. This datastructure may be organized as a table. Further, in some embodiments, asingle table structure 950 may hold usage data and key information formore than one media file, as shown in FIG. 9B.

In accordance with the present disclosure, one embodiment, among others,of a method for managing access to digital media files is shown in theflowchart of FIG. 10. First, in FIG. 10, a user downloads (1010) a mediafile from a media server 160, where the media file has trial accessterms associated with the use of the media file. The trial access termsare received from the media server 160 and may be included as part ofthe data structure containing the media file.

Accordingly, the media file and trial access terms are transferred to acomputer device 130 having a computer application (e.g., media playerapplication 110, media sharing application 160, etc.) for accessing thecontents of the media file. The computer application also monitors(1020) use of the media file and tracks the use of the media file asusage data. Upon a designated event, the computer application checks(1030) whether the trial period, as express by the trial access terms,for the media file has expired. If the computer application detects(1040) that the trial period for a media file has expired and does notauthorize continued use of the media file, the computer applicationpresents (1050) an offer to a user, where the offer enables a user topurchase a license to access the contents of the media file according tonew access terms. Many of these steps are discussed in further detailhereinafter.

With regard to a checking process (1030), a media player application 110or portable computing device 180 (with a portable media playerapplication) may check the trial period for a particular media file in avariety of different ways in a variety of different embodiments. Forexample, in some embodiments, a checking process (where the trial periodis checked) may be performed after each playback request of a particularmedia file by a media player device 110, 180. If the trial period isdetected to have expired, some embodiments authorize the contents of themedia file to be accessed at this time and/or notify a user of theexpired status of the media file.

In some embodiments, a checking process may be performed periodically bya computer application (e.g., media player application 110, portablemedia player application, media sharing application 160) for all or asubset of the media files stored on a device. Also, in some embodiments,a checking process may be performed upon startup of a device 130, 180associated with a media player application 110 and/or media sharingapplication 160 or upon a shutdown of the device 130, 180.

Further, in some embodiments, the checking operation is initiated upondetection of a designated event. For example, if a computer applicationon a general-purpose computer 130 associated with the media sharingapplication 160 detects that a portable computing device 180 has pluggedinto the computer device 130, the media sharing application 160 may thenautomatically check the status of the media files located on theportable computing device 180. Correspondingly, a checking operation mayalso be performed upon the logging in of a user with the media server120, where the check operation is performed for media files that areaccessible by the media sharing application 160. In accordance with thepresent disclosure, one or a combination of different checkingoperations may be performed in various embodiments.

If a media player application 110 or portable computing device 180checks the trial access terms of a particular media file or collectionof media files and further detects that the trial period has expired forone or more media files, a variety of actions may result in a variety ofembodiments. For example, upon detection, a media player application 110may immediately prohibit playback of a media file until a user obtainsthe right for continued use of the media file. Further, upon detection,a media player device 110, 180 and/or a media sharing application 160may notify the user that the trial access terms for the media file donot authorize playback of the contents of the media file. Thisnotification may be done visually by displaying a message or icon on ageneral-purpose computer 130 or portable computing device 180 and/or maybe done by playing an audio alert or message by the general-purposecomputer 130 or portable computing device 180. Further, in someembodiments, a media player application 110, 180 and/or media sharingapplication 160 may internally record that a trial period has expiredfor a particular media file but also authorize continued use of themedia file without immediate notification to the user. Upon a designatedevent (such as a log-in to the media server 120), however, the user isnotified of the expired trial period and is prompted to purchase a newlicensing agreement for continued use of the media file, in someembodiments.

In addition, some embodiments employ digital tokens that may beallocated and distributed from the media server 120 to a media playerdevice 110, 180. For example, a user may purchase a quantity of digitaltokens (e.g., 20) for a particular media player device (e.g., mediaplayer application on a general-purpose computer, a media playerapplication on a portable computing device, etc.) and after expirationof trial access terms for a media file attempting to be accessed by themedia player device, the media player device 110, 180 may exchange a setof the digital tokens allocated for the device for continued use of themedia file. With this approach, a header of the media file may identifythe number of digital tokens required for continued use of the mediafile. Further, different levels of use of the media file may bespecified in the media file header (as part of or in addition to thetrial access terms). For instance, with an exchange of 3 digital tokens,a single playback of the media file may be authorized. Further, with anexchange of 10 digital tokens, a license may be purchased for repeateduse of the media file. Then, when the media player device subsequentlyestablishes communication with the media server 120 (whether directcommunication or indirect communication via a general-purpose computer),the quantity of tokens remaining on the media player device 110, 180 ischecked and the user may be offered an opportunity to purchaseadditional digital tokens.

After detection of an expired trial period of a media file as defined bythe trial access terms for the media file, a user is presented with anoffer to extend usage of the media file. The time at which an offer ispresented to a user may vary for different embodiments. For example, inone embodiment, when a media player application 110, media sharingapplication 160, or other computer application detects that a user isnot authorized to access the contents of a media file, the media playerapplication 110, 180, media sharing application 160, etc. promptlypresents the user an offer to purchase a license for continued use ofthe media file. For example, in some embodiments, the media playerapplication 110 displays a notification on the general-purpose computer130 inviting the user to purchase a license for continued use of themedia file. This license may be of varying scope. For example, it may bea new license that provides limited use of the media file for a numberof plays and/or a length of time. Alternatively, the license may provideunlimited use of the media file with regard to time and number of playsand other potential restrictions. The offer displayed by the mediaplayer application/device 10 may provide a button or link that may beactivated by the user such that the general-purpose computer 130attempts to log into the media server 120 to complete terms of thelicense agreement, to set up financial terms; and/or transfer anynecessary information between the media server 120 and thegeneral-purpose computer 130 (via a media sharing application 160, forexample). In some embodiments, a group of offers are presented to auser, where respective offers may provide varying scopes of use forvarying prices. Also, in some embodiments, an offer presented to a usermay include the option of acquiring a quantity of digital tokens thatcan be used in exchanged for continued use of media files, wheredifferent price plans provide for different quantities of digital tokensto be purchased.

As an illustrative example, FIG. 11 displays a sample interface 1100that may be shown to a user after a trial period has expired for a mediafile, and the user has requested access to the media file. In thisexample, a user has the options of selecting to obtain a license forunlimited use of the media file 1110; selecting to obtain a license forlimited use of the media file 1120; or foregoing the opportunity toobtain a license at this time by selecting the Make Request at AnotherTime button 1130.

In some embodiments, a portable computing device 180 with a portablemedia player application may be limited in size and feature a limitednumber of user interface options, and thus is not capable of displayingor presenting an offer to a user when trial access terms for a mediafile have been determined to have expired. Thus, the portable computingdevice 180 may note (e.g., set an internal flag) or record that use ofthe media file has expired, so that when the portable device 180 isconnected to a general-purpose computer 130, a computer application onthe general-purpose computer 130 can check for expired trial periods onthe portable computing device 180 and present an offer to the user atthat time, if expired trial periods are detected. Alternatively, inembodiments where the portable computing device 180 is capable ofdisplaying an offer for a license, the portable computing device 180 maypresent the offer to the user with instructions for responding to theoffer, such as connecting the portable computing device 180 with thegeneral-purpose computer 130 which is also capable of connecting to themedia server 120.

For example, the media sharing application 160 may be configured todetect that a portable computing device 180 has connected to thegeneral-purpose computer 130. After detection, the media sharingapplication institutes a routine that checks for expired trial periodsassociated with media files on the portable computing device 180. If anexpired trial period is detected, then the media sharing application 160presents an offer to the user for purchasing a new license for continueduse of the media file or else the media file will be deleted or lockedto further access.

Alternatively, in some embodiments, after a user logs into the mediaserver 120 via the general-purpose computer 130, the media server 120accesses contents of the portable computing device 180 if it is alsoconnected to the general-purpose computer 130. Thus, the media server120 checks and detects whether the portable computing device has 180media files with expired trial periods. In addition, the media server120 checks and detects whether the general-purpose computer 130 hasmedia files with expired trial periods. Further, the media server 120 isable to, upon detection, transfer offer materials to the general-purposecomputer 130 that is displayed via the media sharing application 160 formedia files that are located on the portable computing device 180 and/orthe general-purpose computer 130.

Also, in some embodiments, the offer is presented upon a designatedevent, such as logging into the media server 120. For example, to makethe offer to the user, a general-purpose computer 130 may download anoffer from the media server 120 or associated network server. Thus, anoffer is made to the user, after the user has established a connectionbetween the media server 120 and the general-purpose computer 130 andretrieved offer materials.

In other embodiments, offer materials may be prestored in the storagearea of a general-purpose computer 130 housing the media playerapplication 110 and/or media sharing application 160. Thus, thegeneral-purpose computer 130 utilizes the prestored material to presentan offer to a user for accepting a new license agreement.

However, at some point in time, the general-purpose computer 130connects to an external server to transmit the offer and associatedinformation (e.g., name of user, credit card number, agreement form,etc.) to the operator of the media server 120 or other entity authorizedto transfer licenses on behalf of the owner of the contents of the mediafile.

In the case where a user utilizes a portable media player 180 to playmedia files received from a general-purpose computer 130 that previouslydownloaded media files from the media server 180, many differentscenarios exist for triggering the license offering process. Forexample, consider a scenario where the portable computing device 180locally stores one set or library of media files that are not the sameas a second set or library of media files stored on the general-purposecomputer 130. In this scenario, a user can manage each respectivelibrary independently from the other.

In this case, the event that triggers a license offering process mayinvolve one particular event for the general-purpose computer 130 andanother event for the portable computing device 180. Therefore, for thegeneral-purpose computer 130, an event for checking the media filesstored locally on the general-purpose computer 130 may involve theactivation of the media sharing application 160 (e.g., upon launchingthe media sharing application 160). Alternatively, an event for checkingmedia files stored locally on the general-purpose computer 130 mayinvolve a different event of logging into the media server 120, aspreviously explained.

With regard to the portable computing device 180, the media sharingapplication 110 checks the contents of the portable computing device 180when the portable computing device 180 is hooked up or connected to thegeneral-purpose computer 130. Therefore, the event for checking mediafiles stored on the portable computing device 180 involves the detectionof the portable computing device 180 being connected to thegeneral-purpose computer 130 (e.g., automatic plug and play detection).

With regard to a different scenario where the portable media player 180locally stores one set of library media files that are intended to matchthe set of library media files stored on the general-purpose computer130, a single event may be used to trigger the license offering processwith regard to both devices. In this type of scenario, the contents of amedia player application 110 located on the general-purpose computer 130are synched up with contents of a portable media player 180 that isconnected to the general-purpose computer 130 (or vice-versa). In thisway, the contents of the portable computing device 180 is made to beidentically or substantially identical to the contents of the mediaplayer application 110 on the general-purpose computer 130, includingmedia track information, playlists, and usage data. Accordingly, to keepup with usage data, the current usage data maintained by the mediaplayer application 110 on the general-purpose computer 130 and theportable media player 180 is compared with the previous usage data thatwas recorded for a previous “synch” operation.

For example, if at a previous synch operation, the usage was recorded tobe 2 for a particular media (e.g., a song has been played 2 timesbetween the media player application 110 on the general-purpose computer130 and the portable computing device 180) and currently the version ofthe media on the media player application 110 on the computer 130 has ausage amount of 6 and the version of the media on the portable mediaplayer 180 has a usage amount of 9 at the time of the new synchoperation, then the usage amount for the media for both the media playerapplication 110 on the computer and the portable media player 180 isupdated to 11.

In particular, if the media player application 10 on the general-purposecomputer 130 has played the media 4 additional times, since the lastsynch operation (where the usage amount was previously 2) and theportable media player 180 has played the media 7 additional times, sincethe last synch operation (when usage amount was previously 2) on theportable media player 180, then the new usage amount is the previoususage amount (which was 2) plus the additional usage amounts for eachdevice (which is 2+7=9) for a total usage amount of 11 (i.e., 2+9).Therefore, after the new synch operation, the usage amount is 11 forboth the portable computing device 180 and the media player application110 on the general-purpose computer 130 (until one of the devices usesthe media for an additional time, before another synch operation isperformed).

In a case where a user has a media player application 110 stored on ageneral-purpose computer 130 (or other communication device) thatcommunicates with a media server 120, one embodiment, among others, ofan approach for generating an offer to purchase a media license isrepresented in the flowchart of FIG. 12. In this example, the mediaplayer application 110 receives (1210) a request to play a particularmedia file. In response, the media player application 110 checks (1220)for a trial period associated with the particular media file. If themedia player application 110 does not find an associated trial period,the media player application 110 proceeds to play the media file.However, if the media player application 110 does find an associatedtrial period, the media player application 110 determines (1230) if thetrial period has not expired and authorizes playing of the media file.If the trial period has not expired and the media file is authorized tobe played, then the media file is played (1240) and usage data isupdated, if warranted, by the player 110 or reported to the mediasharing application 160, so that it may update the necessary files.

The media player, in some embodiments, notifies (1250) the user of theexpired trial period via an audible media or message. In otherembodiments, the media player application 110 may display a visualmessage or icon denoting the expiration of the trial period or usage.Also, the media sharing application 160 routinely checks (1260) forexpired trial periods (e.g., at launching of the media sharingapplication 160, after logging into media server 120, etc.) and upondetection of an expired limitation, displays (1270) an offer screeninterface for purchasing a new license for the expired media. The offerscreen interface may provide a variety of different licensing options(e.g., purchasing song for unlimited duration, purchasing extended useof media for limited duration, purchasing use of media for unlimitedplaybacks, purchasing for limited playbacks, etc., as generallydemonstrated in FIG. 11) and prompts the user to select an option and toprovide information for purchasing one of the options. Further,information provided by the user is relayed to the media server 120(e.g. by media sharing application, other computer application, etc.),and information provided by the media server 120 is relayed to the uservia the media sharing application 160. After a license is purchased,then modifications, as necessary, are made (1280) to the media file andassociated usage data to enable use of the media file in accordance withthe purchased license. For example, parameters may be added or modifiedto a header of a media file to indicate that the media file is subjectto a new trial period or is subject to a new licensing agreement thatauthorizes unlimited use of the media file.

Referring now to FIG. 13, one embodiment of a license offering processis described. The process begins in step 1310 in which a user registersor subscribes to a media sharing account or plan that offers the userthe opportunity to download media (as embodied in media files) that areon included on a list of media, where the list of media changes overtime (e.g., dynamically), and use downloaded media for a trial period,where the trial period includes the amount of time that the downloadedmedia is on the list of media. For example, one embodiment may utilize amedia chart, such as the Top 40 chart, as the list of media (e.g., “songlist”) that determines the trial period for downloaded media. Anotherembodiment may involve a list of media according to a particular genre,such “Golden Oldies” or “Irish Folk Songs,” for example. As a mediafalls or rotates off the media list, then the user is provided anopportunity to obtain or purchase a license for continued use of themedia that is no longer on the media list.

Accordingly, referring back to FIG. 13, the user is provided (1320) thecurrent list of media that are available for download by the user (e.g.,via a media sharing application 160). From the media list, the userdownloads (1330) one or more media from the media list (e.g., via themedia server 120). Then, each time that the user logs into his or hermedia sharing account, the media previously downloaded by the user arechecked (1340) to determine whether the media are still included on themost recent version of the media list (e.g., via the media sharingapplication 160) maintained by the media sharing service administeringthe media sharing account) and the trial periods for the media haveexpired. If a downloaded media is still listed on the media list, thenthe trial period has not expired and the user maintains (1350) continueduse of the media. Alternatively, if the downloaded media is no longerlisted on the media list, then the trial period for the media hasexpired. In some embodiments, at this time, the user is not authorizedto continue use of the media. While in others, the user is allowed touse the media for an extended period (e.g., a grace period) to providethe user an opportunity to obtain a license for continued use of themedia. In some embodiments, a user is periodically logged into his orher media sharing account or an event triggers a log-in process, such asan operation to synch a portable media device with a computer that iscapable of connecting to a server maintained by a media sharing service(e.g., a media server 120).

As a result of the expired trial period, the user is offered (1360) anopportunity to obtain a new license for continued use of the expiredmedia. In some embodiments, the user may be provided a certain period inwhich he or she can accept or reject the offer. Accordingly, in someembodiments, a time stamp parameter may be included in the trial accessterms to indicate when time has expired for responding to the offer forobtaining a new license.

If the user rejects the offer to obtain a new license, the downloadedmedia that is no longer on the media list is configured (1370) to beinaccessible by the user (e.g., by deleting a media file or modifyingthe media file or associated files, such as trial access terms orencryption/decryption key, to deactivate the ability to access the mediafile). Alternatively, if the user accepts the offer and obtains alicense for continued use of the downloaded media, the media file forthe media is configured (1380) to be available by the user for continueduse of the media file (e.g., configuring trial access terms to indicateto indicate that the media file is not subject to a trial period and isavailable for continued use, maintain an associatedencryption/decryption key for the media file, etc.).

Further, in some embodiments, the next time that the user logs into hisor her media sharing account associated with the media server 120 wherethe user downloads his or her media files, the media sharing serviceadministering the user's media sharing account debits or charges theuser's account for a fee associated with the license the user obtainedto have continued use of the downloaded media.

Embodiments of the present disclosure can be implemented in software(e.g., firmware), hardware, or a combination thereof. For example, insome embodiments, the media player application 110 and media sharingapplication 160 are implemented in software, as an executable program,and is executed by a special or general-purpose digital computer, suchas a personal computer (PC; IBM-compatible, Apple-compatible, orotherwise), workstation, minicomputer, or mainframe computer. An exampleof a general-purpose computer that can implement various components ofpresent disclosure is shown in FIG. 14.

Generally, in terms of hardware architecture, as shown in FIG. 14, thecomputer 1411 includes a processor 1412, memory 1414, and one or moreinput and/or output (I/O) devices 1416 (or peripherals) that arecommunicatively coupled via a local interface 1418. The local interface1418 can be, for example but not limited to, one or more buses or otherwired or wireless connections, as is known in the art. The localinterface 1418 may have additional elements, which are omitted forsimplicity, such as controllers, buffers (caches), drivers, repeaters,and receivers, to enable communications. Further, the local interfacemay include address, control, and/or data connections to enableappropriate communications among the aforementioned components.

The processor 1412 is a hardware device for executing software,particularly that stored in memory 1414. The processor 1412 can be anycustom made or commercially available processor, a central processingunit (CPU), an auxiliary processor among several processors associatedwith the computer 11, a semiconductor based microprocessor (in the formof a microchip or chip set), a macroprocessor, or generally any devicefor executing software instructions. Examples of suitable commerciallyavailable microprocessors are as follows: a PA-RISC seriesmicroprocessor from Hewlett-Packard Company, an 80x86 or Pentium seriesmicroprocessor from Intel Corporation, a PowerPC microprocessor fromIBM, a Sparc microprocessor from Sun Microsystems, Inc, or a 68xxxseries microprocessor from Motorola Corporation.

The memory 1414 can include any one or combination of volatile memoryelements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM,etc.)) and nonvolatile memory elements (e.g., ROM, hard drive, tape,CDROM, etc.). Moreover, the memory 1414 may incorporate electronic,magnetic, optical, and/or other types of storage media. Note that thememory 1414 can have a distributed architecture, where variouscomponents are situated remote from one another, but can be accessed bythe processor 1412.

The software in memory 1414 may include one or more separate programs,each of which comprises an ordered listing of executable instructionsfor implementing logical functions. In the example of FIG. 14, thesoftware in the memory 1414 includes a media player application 110, amedia sharing application 160, trial period checking logic 1430configured to retrieve a new dynamic list and check whether a trialperiod for a media file has expired by determining whether the mediafile is listed on the new dynamic list, and offer presentation logic1440 configured to offer a user a license for continued use of a mediafile that has an expired trial period, in accordance with the presentdisclosure, and a suitable operating system (O/S) 1422. A nonexhaustivelist of examples of suitable commercially available operating systems1422 is as follows: (a) a Windows operating system available fromMicrosoft Corporation; (b) a Netware operating system available fromNovell, Inc.; (c) a Macintosh operating system available from AppleComputer, Inc.; (d) a UNIX operating system, which is available forpurchase from many vendors, such as the Hewlett-Packard Company, SunMicrosystems, Inc., and AT&T Corporation; (e) a LINUX operating system,which is freeware that is readily available on the Internet; (f) a runtime Vxworks operating system from WindRiver Systems, Inc.; or (g) anappliance-based operating system, such as that implemented in handheldcomputers or personal data assistants (PDAs) (e.g., PalmOS availablefrom Palm Computing, Inc., and Windows CE available from MicrosoftCorporation). The operating system 1422 essentially controls theexecution of other computer programs and provides scheduling,input-output control, file and data management, memory management, andcommunication control and related services.

A system component embodied as software may also be construed as asource program, executable program (object code), script, or any otherentity comprising a set of instructions to be performed. When a sourceprogram, then the program is translated via a compiler, assembler,interpreter, or the like, which may or may not be included within thememory 1414, so as to operate properly in connection with the O/S 1422.

The I/O devices 1416 may include input devices, for example but notlimited to, a keyboard, mouse, scanner, microphone, etc. Furthermore,the I/O devices 1416 may also include output devices, for example butnot limited to, a printer, display, etc. Finally, the I/O devices 1416may further include devices that communicate both inputs and outputs,for instance but not limited to, a modulator/demodulator (modem; foraccessing another device, system, or network), a radio frequency (RF) orother transceiver, a telephonic interface, a bridge, a router, etc.

If the computer 1411 is a PC, workstation, or the like, the software inthe memory 1414 may further include a basic input output system (BIOS)(omitted for simplicity). The BIOS is a set of essential softwareroutines that initialize and test hardware at startup, start the O/S1422, and support the transfer of data among the hardware devices. TheBIOS is stored in ROM so that the BIOS can be executed when the computer1411 is activated.

When the computer 1411 is in operation, the processor 1412 is configuredto execute software stored within the memory 1414, to communicate datato and from the memory 1414, and to generally control operations of thecomputer 1411 pursuant to the software. Software in memory, in whole orin part, are read by the processor 1412, perhaps buffered within theprocessor 1412, and then executed.

It should be noted that the software components can be stored on anycomputer readable medium for use by or in connection with any computerrelated system or method. In the context of this document, a computerreadable medium is an electronic, magnetic, optical, or other physicaldevice or means that can contain or store a computer program for use byor in connection with a computer related system or method. In thecontext of this document, a “computer-readable medium” can be any meansthat can store, communicate, propagate, or transport the program for useby or in connection with the instruction execution system, apparatus, ordevice. The computer readable medium can be, for example but not limitedto, an electronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, device, or propagation medium. Morespecific examples (a nonexhaustive list) of the computer-readable mediumwould include the following: an electrical connection (electronic)having one or more wires, a portable computer diskette (magnetic), arandom access memory (RAM) (electronic), a read-only memory (ROM)(electronic), an erasable programmable read-only memory (EPROM, EEPROM,or Flash memory) (electronic), an optical fiber (optical), and aportable compact disc read-only memory (CDROM) (optical). Note that thecomputer-readable medium could even be paper or another suitable mediumupon which the program is printed, as the program can be electronicallycaptured, via for instance optical scanning of the paper or othermedium, then compiled, interpreted or otherwise processed in a suitablemanner if necessary, and then stored in a computer memory.

If implemented in hardware, as in an alternative embodiment, variousembodiments can be implemented with any or a combination of thefollowing technologies, which are all well known in the art: a discretelogic circuit(s) having logic gates for implementing logic functionsupon data signals, an application specific integrated circuit (ASIC)having appropriate combinational logic gates, a programmable gatearray(s) (PGA), a field programmable gate array (FPGA), etc.

It should be emphasized that the above-described embodiments of thepresent disclosure, are merely possible examples of implementations,merely set forth for a clear understanding of the principles of thedisclosure. Many variations and modifications may be made to theabove-described embodiment(s) of the disclosure without departingsubstantially from the spirit and principles of the disclosure.

For example, as noted above, the invention is not limited to sharing ofany specific type of digital media files. The principles of the presentdisclosure may be extended to any form of digital media, includingaudiovisual files. To illustrate, in some embodiments, a media videofile may be subject to trial access terms, such that after expiration ofthe trial access terms, limited use of the media video file isauthorized. In particular, after expiration of trial access terms forthe media video file, the video portion of the media video file may beprohibited from being played by a media player application, while theaudio portion is allowed to be played or vice versa.

All such modifications and variations are intended to be included hereinwithin the scope of this disclosure.

1. A method comprising: accessing by a user device a dynamic list ofmedia files stored on a file server; downloading by the user device amedia file listed in the dynamic list of media files; accessing a mediafile when the media file is listed in the dynamic list; detecting anevent trigger for accessing the dynamic list of media files; accessingan updated dynamic list of media files in response to detecting theevent trigger; determining that the media file is not listed in theupdated dynamic list; and setting the media file as unavailable foraccess by the user device when the media file is not listed in theupdated dynamic list.
 2. The method of claim 1 further comprising:prompting a user to obtain a license for access to the media file thatis not list in the updated dynamic list; and granting access to themedia file by the user after the user obtains the license.
 3. The methodof claim 2 wherein the user is provided a grace period for responding tothe prompting step.
 4. The method of claim 2 further comprising:configuring the media file to be inaccessible by the user if the userchooses not to obtain the license for the media file that is not listedin the updated dynamic list.
 5. The method of claim 2 wherein promptingthe user to obtain the license is triggered by detecting expiration of atrial period for the media file, the trial period corresponding to aperiod of time that the media file is included in the dynamic listbefore the media file is removed from the dynamic list.
 6. The method ofclaim 1 wherein the event trigger is selected from a group consisting ofwhen a portable media device is connected to the user device, and whenaccess to the media file is requested.
 7. The method of claim 1 furthercomprising: displaying a list of media files that are available fordownload by the user device, the list of media files including mediafiles contained in the dynamic list and excluding media files previouslydownloaded by the user device.
 8. The method of claim 1 furthercomprising: detecting a connection of a portable media device to theuser device that is used to download the media file from the dynamiclist; and checking trial periods of the media file located on theportable media device and the user device.
 9. The method of claim 1wherein the dynamic list is organized by music genre.
 10. The method ofclaim 1 wherein the dynamic list is organized by a current popularity ofthe media files.
 11. A method comprising: receiving by a portable mediadevice a media file listed in a dynamic list of media files stored on afile server from a user computer; disconnecting the portable mediadevice from the user computer; accessing by the portable media devicethe media listed in the dynamic list of the media file when the portablemedia device is disconnected from the user computer; connecting theportable media device to the user computer; receiving an updated dynamiclist of media files stored on the file server from the user computerwhen the portable media device is connected to the user computer; andsetting the media file as unavailable for access by the portablecomputer when the media file is not listed in the updated dynamic list.12. The method of claim 11 wherein the media file includes a sound file.receiving by the portable media device a grace period when the usercomputer has prompted a user to obtain a license for access to the mediafile that is not listed in the updated dynamic list; and configuring themedia file to be accessible during the grace period.
 13. The method ofclaim 12 wherein the media file includes a sound file. receiving by theportable media device a indication from the user computer that user haschosen not to obtain the license for access to the media file that isnot listed in the updated dynamic list, wherein the indication isreceived when the portable media device connects to the user computer;and configuring the media file to be inaccessible when the user choosesnot to obtain the license.
 14. The method of claim 12 wherein promptingthe user to obtain the license is triggered by detecting expiration of atrial period for the media file, the trial period corresponding to aperiod of time that the media file is included in the dynamic listbefore the media file is removed from the dynamic list.
 15. A portablemedia device comprising: a processor; and a memory connected to theprocessor, the memory storing instructions when executed cause theprocessor to perform steps of: access by the portable media device adynamic list of media files stored on a file server; download by theportable media device a media file listed in the dynamic list of mediafiles; access the media file; detect an event trigger for accessing thedynamic list of media files; access an updated dynamic list of mediafiles in response to detecting the event trigger; determine that themedia file is not listed in the updated dynamic list; and set the mediafile as unavailable for access by the portable media device when themedia file is not listed in the updated dynamic list.
 16. The portablemedia device of claim 15 wherein the instructions when executed furthercause the processor to perform the steps of: prompt a user to obtain alicense for access to the media file that is not list in the updateddynamic list; and grant access to the media file by the user after theuser obtains the license.
 17. The portable media device of claim 16wherein the instructions when executed further cause the processor toperform the steps of: configure the media file to be inaccessible by theportable media device if the user chooses not to obtain the license forthe media file that is not listed in the updated dynamic list.
 18. Theportable media device of claim 16 wherein prompting the user to obtainthe license is triggered by detecting expiration of a trial period forthe media file, the trial period corresponding to a period of time thatthe media file is included in the dynamic list before the media file isremoved from the dynamic list.
 19. The portable media device of claim 15wherein the instructions when executed further cause the processor toperform the steps of: display a list of media files that are availablefor download by the portable media device, the list of media filesincluding media files contained in the dynamic list and excluding mediafiles previously downloaded by the portable media device.
 20. Theportable media device of claim 15 wherein the instructions when executedfurther cause the processor to perform the steps of: detect a connectionof the portable media device to a user computer that is used to downloadthe media file from the dynamic list; and checking trial periods of themedia file located on the portable media device and the user computer.